package common.service.util;

import java.security.MessageDigest;


public class MD5Util {

	private static String key="87228c3b56564585f";
	
	
	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++){

			resultSb.append(byteToHexString(b[i]));
		}

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0){
			n += 256;
		}
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname)){

				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			} else{

				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
			}
		} catch (Exception exception) {
		}
		return resultString;
	}

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	public static final String md5Digest(String src) throws Exception {
		if (src == null) {
			return "";
		} else {
			src=src+key;
			char[] hexDigits = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
			MessageDigest alg = MessageDigest.getInstance("MD5");
			byte[] tmp = alg.digest((src).getBytes("UTF-8"));
			char[] str = new char[32];
			int k = 0;

			for(int i = 0; i < 16; ++i) {
				byte byte0 = tmp[i];
				str[k++] = hexDigits[byte0 >>> 4 & 15];
				str[k++] = hexDigits[byte0 & 15];
			}

			return new String(str);
		}
	}
	
}
